With the latest circular Lightlog board fully populated with components you can see almost all parts are now on the top side of the board, making it easier to solder them in one go using solder paste (applied using a solder mask stencil). The solder is then heated using a hot air gun from above, or a hot plate from below. Placing components on the solder paste is now the slowest manual step, taking perhaps 10 to 15min, it’s a little fiddly if you don’t have patience and a steady, tweezer hand!
In the image above, the chip at the top is the 64Kbytes of EEPROM memory. On the left of the board is the PICAXE-14M2 micro-controller. The centre and right of the board hold the HM-11 Bluetooth LE 4.0 module (the antenna is on the right edge). Along bottom edge are five white LEDs for indicating the current light goal and ambient brightness. Near the bottom, just above the central LED, is the TAOS TCS34725FN digital colour sensor used for tracking the ambient light and colour conditions.
The components on the back of the board need to be soldered by hand, after the components on the front are soldered, but as there are only two large components it is a quick step to complete. In the image above, the 3V CR2032 battery holder is in the centre, and tactile press switch at the bottom. Pressing and holding the switch down for 2 seconds triggers the LEDs to display your current daily light goal achieved so far, and will attempt to synchronise data via Bluetooth if you’ve linked it to your smart phone, tablet, or computer – the code for this is still a little rough still, but will go up into the git repository (again under an Open Source license as per other parts of this project) once the more obvious kinks are ironed out.